Partial support is requested to the Keystone Symposium, "Molecular Biology of Muscle Development", to be held at the Snowbird Conference Center, Snowbird Utah from April 11-17, 1994. This is the third Keystone symposium on skeletal muscle biology and will focus on recent advances in what has become one of the most active areas of research for studying basic mechanisms of cell determination, as well as the relationship between cell proliferation and differentiation. Skeletal myoblasts arise from mesodermal stem cells that become committed to the myogenic lineage. Skeletal differentiation is linked to the withdrawal of myoblasts form the cell cycle and is accompanied by transcriptional activation of structural and regulatory genes. The control regions of numerous muscle-specific genes have been defined and shown to interact with cell-type specific as well as widely expressed transcription factors. Among these are the members of the MyoD family of helix-loop-helix proteins, which can activate myogenesis in a variety of non-muscle cell types. These and other recently discovered factors function within a regulatory network that influences muscle cell differentiation and growth. Novel transgenic animal models have facilitated the application of knowledge gained in muscle cell culture systems to an understanding of muscle development in vivo. The groundwork has been laid for unprecented advances in elucidating the molecular mechanisms underlying the specification of embryonic skeletal muscle precursors, the generation of muscle fiber diversity, the control of myoblast proliferation and differentiation in developing and aging muscle, and the genetic dissection of neuromuscular disorders. The meeting is intended to bring together researchers with a broad range of interests and expertise to provide a comprehensive and multidisciplinary view of this rapidly moving field. The program will integrate areas of recent progress in the molecular biology of skeletal muscle, with special emphasis on mechanisms of development. The meeting will be organized into ten plenary sessions (for oral presentation), three workshops focusing on recent advances in more specialized topics of high current interest which will allow discussion and scientific exchange between participants, and four poster sessions, with ample time for informal exchange of observations and ideas. Approximately 350 foreign and domestic scientists will be in attendance; the participants will be selected on the basis of the quality of their work and how it will enhance the meeting. g Conferees will represent all levels of scientists from graduate student to senior investigators. The overall goal of this meeting is to allow a synthesis of ideas from different areas of muscle developmental biology, and the formulation of new concepts for future directions of research in this field.